Transcript 1. Artificial Selection-observation that selective breeding of crops

1. Artificial Selectionobservation that selective
breeding of crops and animals
by farmers could produce
more desirable offspring.
• Homologous Structures- traits that are
similar in different species because
species share a common ancestor. same
structure/different function
•
•
Analogous Structures- Do not have
common evolutionary origin.
different structure/same function
Vestigial Structure- structures
that are inherited but often
unused!
•
Adaptation- evolution of a structure,
behavior, or internal process that
enables an organism to respond to
environmental factors and to live to
produce offspring.
– change to better suit its environment
•
This bird has developed a long beak to
better reach nectar in flowers
Genetic Drift- the alteration of
allelic sequences by chance
events
Amish people and the higher
percentage of children born with
6 fingers
•
Speciation- evolution of a new
species
– birds where all the same species until the
birds adapted and start to develop beaks
that were better suited to eat certain foods
•
Reproductive Isolation- formerly
interbreeding organims can no longer
mate and produce fertile offspring.
The genes have become too different
– can result from animals being separated
geographically or from animals mating at
different seasons
Mates in the summer
Mates in the Winter
Geographic isolation
1. Geographic Isolation- physical barrier
divides a population; rivers, volcanic
eruptions, earthquakes, etc.. The
species can no longer breed together
because they have become two
different species
1. Divergent evolution- specis that were
once similar to an ancestral species
diverge, or become increasingly
distinct.
Species become
less similiar
Adaptive radiation
Hawaiian Niches
Adaptive radiation
Hawaiian Honeycreeper
1. Convergent Evolution- a pattern of
evolution in which distantly related
organisms evolve similar traits.
Species
Develop
Similar
characterstics
The answer is
convergent
evolution. Dolphins
and sharks are
unrelated organisms
that have evolved
similar traits because
they share similar
environmental
pressures.